Pneumatic vise with high clamping force

ABSTRACT

A clamping device, such as a vise, is operated by a piston and cylinder movable by a fluid under pressure, preferably a pneumatic cylinder, and a wedge is used to transmit the force of the piston to a movable member of the clamping device.

Tlnfite States Paiei Riggin 1451 Nev. 12, 1974 PNEUMATHC VlSlE WHTH 111G111 CLAMPHNG 1,869,631 8/1932 Swanson 269/234 FORCE 2,656,748 10/1953 Hugo et ul........ 269/32 X 2,840,381 6/1958 Mersek 269/234 x lnvcntorl Anwnmfl gg Corso P 3,192,600 7/1965 Jones .1 269/234 x 16152 Gen0vz1-Cornigliano, Italy [22] Filed: Get. 18, 1972 Primary Examiner-Roy Lake [21] Appl 298598 Assistant Examiner-Neil Abrams [30] Foreign Application Priority Data Oct, 26. 1971 Italy 13006/71 Sept. 7, 1972 Italy 12880/72 57 STR [52] US. Cl 269/32, 269/221, 269/234 I e 511 1111. (:1 B251) 11/18 A Clampmg devm- Such as penned by P [58] Field of Search 269/27, 32 221423, ton and cylinder movable by 11 fluid under pressure. 269/234 preferably a pneumatic cylinder, and 21 wedge is used 1 to transmit the force of the piston to a movable mem- [56] References Cited ber of the clamplng device.

UNITED STATES PATENTS 1,751,329 3/1930 Hancock 269/221 1 Claim, 3 Drawing Figures PNEUMATIC VISE WITH HIGH CLAMFING FORCE Work clamping tools, especially vises, operated by fluids under pressure, such as air or oil, are nowadays very much used in industry. In spite of numerous advantages, compressed air has the disadvantage of being usually available only at rather low pressures, generally at 6 or 8 atm. Therefore, to obtain large working forces, it is necessary to resort to large cylinders, which however cannot be used in rather small vises or other small equipment.

This disadvantage can be avoided by interposing between the pneumatic cylinder and the movable unit of the tool, a system reducing the stroke which, by reducing the stroke of the tool as compared with the stroke of the piston, increases the working force inversely as the stroke is reduced.

To this purpose many systems are used today, such as a screw system operated by a pinion-rack or an endless screw-worm wheel group, or a toggle lever system.

The present invention provides a new clamping detapped bore in wedge 10. In member there is mounteda roll 11, suitable to support the forces exerted by pneumatic cylinder 8 on wedge and to facilitate the sliding of the wedge 10 along roll ll.

Roll 12 ismounted in member 6 and is similar to roll 11. Roll 12 is suitable to receive the working force exerted by wedge 10 and to facilitate the sliding of the inclined surface of the wedge 10. Screw 13 is connected to member 5 in a conventional manner to enable manual opening and closing of jaws 2 and 4. When the manual adjustment via screw 13 is completed, member 5 remains fixed with respect to jaw 2, and only member 6 is actually movable under the action of cylinder 8 an wedge 10.

vice, such as a vise, having a movable jaw which is moved by a pneumatic piston and cylinder through the intermediary of a wedge so arranged as to provide a working force inversely proportional to the tangent of the angle of the vertex of the wedge. In a preferred embodiment of the invention, the clamping device is a vise having a fixed jaw and a movable jaw, the movable jaw having, in turn, a support member and a movable member. The movable jaw and the support and movable members thereof are movable along a guide member toward and away from the fixed jaw. A pneumatic piston and cylinder is arranged with its axis inclined, and preferably perpendicular, to the axis of the guide member, and the wedge is fixed to one end of the piston and between the support member and movable member of the movable jaw in such a way that when the piston.

moves the wedge, the wedge slides with one face against the support member of the movable jaw and the other face against the movable member of the movable jaw so that the movable jaw closes toward the fixed jaw. To minimize friction that would result if the wedge is pushed between fixed surfaces, it is preferred to have the wedge act between two rolls, one in the support member and the other in the movable member of the movable jaw, in order to change the sliding friction into rolling friction.

The present invention is illustrated as an embodiment in the enclosed drawing where:

FIG. 1 is a side view in partial section taken along line A-A of FIG. 2 of a vise according to the invention;

FIG. 2 is a top view of the vise in partial section taken along line 8-8 of FIG. I; and

FIG. 3 is a section of the vise taken along line C-C of FIG. 2.

Referring to the drawings, the vise has a support or backing plate 1 on which is mounted fixed jaw 2 at one end and, in the upper part, sliding guides 3. Movable jaw 4 slides along guides 3.

The movable jaw 4 has members 5 and 6 which are connected by spring member 7. At a right angle to guides 3 is pneumatic cylinder 8 and piston 8a to which is secured shaft 9. A wedge 10 having a relatively small angle a at its vertex is fastened to shaft 9 by suitable means, such as by screwing the end of shaft 9 into a The operation of the device :is as follows. Compressed air is led into cylinder 8 from an external source (not shown) and piston 9 moves to the right (as viewed in FIG. 2), thereby moving wedge 10 between rolls 111 and 12. Roll 12 is thus caused to move along the inclined section of the wedge against the bias of spring member 7, thereby moving movable jaw 4 along guides 3 toward fixed jaw 2 to. tighten the workpiece between jaws 2 and 4. The action of the compressed air cylinder is thus magnified by the wedge 10 inversely to the tangent of an angle a at the vertex of the wedge.

The invention has been described above as an embodiment and not as a limitation thereof. The invention can in practice undergo various changes and amendments according to the wide range of clamping tools, to which the vise illustrated belongs, as well as to pro vide the replacement of parts by similar ones remaining within the scope of the following claims. For example, rolls ll and 12 may be replaced by multiple rolls or roller bearings or other roller friction systems.

What is claimed is:

l. A clamping device for exerting substantially large working forces to hold a workpiece, comprising, in combination, a plate, a fixed clamping member and a movable clamping member between which said work piece is held; a support member for supporting said movable clamping member; a pneumatic piston and stationary cylinder on said support member; a wedge member connected to said piston, said wedge member moving said movable clamping member toward said fixed clamping member when said pneumatic piston is actuated within said stationary cylinder, the working force moving said movable clamping member being inversely proportional to the tangent of the angle of the vertex of the wedge of said wedge member; spring means uring said movable clamping member toward said support member, said wedge member being secured to an end of the piston and being located between said support member and said movable clamping member, said wedge member moving said movable clamping member away from said support member against the bias of said spring means when said piston is actuated, said piston and wedge member moving along a path of travel perpendicular to the path of travel of said movable clamping member; a first roll member rotatable on said movable clamping member with axis of rotation movable with said movable clamping member; a second roll member rotatable on said support member, the axis of rotation of said second roll member being stationary, said wedge member being movable by said piston between said first and second roll members for rotating said roll members when said movable clamping member is forced against said fixed movable clamping member being movable by said piston and wedge member relative to said screw means,

when said screw means is stationary. 

1. A clamping device for exerting substantially large working forces to hold a workpiece, comprising, in combination, a plate, a fixed clamping member and a movable clamping member between which said workpiece is held; a support member for supporting said movable clamping member; a pneumatic piston and stationary cylinder on said support member; a wedge member connected to said piston, said wedge member moving said movable clamping member toward said fixed clamping member when said pneumatic piston is actuated within said stationary cylinder, the working force moving said movable clamping member being inversely proportional to the tangent of the angle of the vertex of the wedge of said wedge member; spring means uring said movable clamping member toward said support member, said wedge member being secured to an end of the piston and being located between said support member and said movable clamping member, said wedge member moving said movable clamping member away from said support member against the bias of said spring means when said piston is actuated, said piston and wedge member moving along a path of travel perpendicular to the path of travel of said movable clamping member; a first roll member rotatable on said movable clamping member with axis of rotation movable with said movable clamping member; a second roll member rotatable on said support member, the axis of rotation of said second roll member being stationary, said wedge member being movable by said piston between said first and second roll members for rotating said roll members when said movable clamping member is forced against said fixed clamping member; adjusting screw means on said plate and connected to said movable clamping member and said support member for moving said movable clamping member and said piston and wedge member, said movable clamping member being movable by said piston and wedge member relative to said screw means, when said screw means is stationary. 